1. 5.1 An Introduction to blood
Unit 5 serology
5.1 An Introduction to blood

2. Components of Blood Solid portion of the blood 1. Erythrocytes
Red blood cells (RBC).
Contain hemoglobin that transports the oxygen and carbon dioxide.
Concave in structure.
Approximately 30 trillion in the blood.

3. Components of Blood 2. Leukocytes White blood cells (WBC).
Provide immunity for the body and produce antibodies.
There are 5 types of white blood cells.
Approximately 430 billion in the blood.

4. Components of Blood 3. Thrombocytes
Platelets (pieces of larger cells).
Responsible for starting the clotting process by making fibrin to form a clot.

5. Components of Blood Liquid portion of the blood 1. Plasma
Fluid portion of the blood that carries the RBC, WBC, and platelets.
55% of blood is the plasma.
Made up of 90% water and 10% metabolites (salt, ions, and proteins).

6. Blood Type ABO blood classification system 1. Antigens
Proteins found on the surface of every RBC.
There are over 100 different antigens in the human blood.
Two of the antigens, labeled as A and B, are the ones used on the RBC surface to determine blood type.
If antigen A is present a person is A blood type.
If antigen B is present a person is B blood type.
If both antigens A & B are present a person is AB blood type.
If neither antigens A & B are present a person is O blood type.

8. Blood Type 2. Antibodies 3. Rh Factor (Rhesus factor)
Manufactures by some of the WBC and found in the blood serum.
Function is to attack any invader (antigen) that enters the bloodstream that does not belong in your system.
A person has antibodies again antigens that are not found on the surface of their own RBC.
3. Rh Factor (Rhesus factor)
Antigen found on the surface of a RBC.
If a person has the Rh antigen they are Rh positive (Rh+).
If a person does not have the Rh antigen they are Rh negative (Rh-).

9. Determination of Blood Type
Your blood is tested by adding blood cells of a known type.
Remember, your blood has antibodies for the other antigens. These antibodies will cause the blood to agglutinate if the type you added doesn’t match the type of the blood you are testing.
For example, if you add type B red blood cells to type A blood, it will agglutinate.
So, if you add a known blood type to a sample and it doesn’t agglutinate-you know the blood types are the same.

11. Determine genetic probabilities using blood types
Punnet Squares: A parent passes on one of two genes for blood type to the offspring. One of two genes is also passed on for the Rh factor.
In order to be recessive in type or Rh, BOTH genes must be recessive.
Using a Punnet square can determine if a blood type is possible in an offspring.
Genotypes:
Heterozygous-the genes are different (one dominant and one recessive)
Homozygous-the genes are the same (either both are dominant or both are recessive)

12. Determine genetic probabilities using blood types
If a child’s blood type is AB (IAIB), the mother’s type is AB (IAIB) and the father’s type is O (ii), could the “father” be the genetic father? IA IB i i

13. Genetic Probabilities
Typical blood typing distribution in the United States.
Blood Type
Percentage A
40% B
11% AB 4% O
45%
Rh+
85%
Rh-
15%